Patch is a convenient and effective dosage form used for protection of a wound or administration of a physiologically active ingredient to living organisms. However, since its form is flat and plane and has a large surface area, the quality of patch is susceptible to influence from the environment outside the patch. Hence, the package structure thereof needs to be improved.
JP-A-2001-9985 discloses a patch package structure using a package comprising a low density polyethylene (hereinafter to be referred to as “LDPE”) layer, and an LDPE layer comprising an inorganic filler dispersed therein, an aluminum foil and a high density polyethylene (hereinafter to be referred to as “HDPE”) layer laminated in this order on the LDPE layer. However, such patch package structure may decrease the content of a physiologically active ingredient in the patch, since the innermost layer of the packaging member is made of LDPE, which absorbs the physiologically active ingredient. In addition, since the LDPE layer has poor rigidity, when a physical impact from the outside is applied to the packaging member, the patch easily suffers from the impact.
An adhesive layer of a patch may contain an organic liquid component for the purpose of plasticization of an adhesive or controlling adhesiveness of an adhesive layer to an adhesion site, controlling transdermal absorbability of a physiologically active ingredient when an adhesive layer contains the physiologically active ingredient, and the like. In a patch containing such organic liquid component, the content of an organic liquid component may decrease during preservation in a packaging member and the desired adhesiveness and transdermal absorbability of the physiologically active ingredient may be difficult to obtain.